Corsair Vengeance LPX DDR4-2666 Review

Frustrated in my efforts to find a better-overclocking DDR4 kit than the one I’ve been using, I first found sets with slightly less capability, but twice the capacity. Then I discovered a kit with a similar rating, but a lower price. Finally, I looked at an alternative with similar overclocking headroom and more features. If my only purpose was to find faster RAM, I was not successful.

Maybe a lower price would sweeten the juice. And perhaps it’s time I stop thinking like a reviewer and start pretending it’s my money. I mean, how many overclockers really want to pay more for their RAM than they paid for their high-end motherboard? For many of us, overclocking has always been about value!

With Kingston’s almost-value-priced DDR4-3000 barely able to overclock past its rating, I began to wonder if a lower-rated part from an overclocking-focused brand might be a little more flexible. Corsair’s Vengeance LPX looks the part, particularly in its CMK16GX4M4A2666C15R (that last R is for Red) limited edition. It’s cheaper than Kingston’s parts, and if it can match them in an overclock, we just might find a top enthusiast value.

Encouragement for this value-finding mission is spotted in the Vengeance LPX XMP registers, where we see that its DDR4-2666 rating comes at a mere 1.2V. Corsair even adds an XMP-2800 entry, just to act as a starting point for real overclocking. The rated timings aren’t great though.

Rated Specifications

Fortunately, as the DDR4-2800 XMP value shows, these are designed for overclocking. We’re putting them up against the previously-reviewed HyperX Predator today, while the reference kit that G.Skill sent serves its purpose by setting the high mark.

Something we noticed in our previous DDR4-2800 review was our motherboard’s tendency to use the CPU’s 1.25x BCLK strap whenever fast memory is used. One might expect the same board to use the default 100MHz strap whenever an Intel-enabled data rate is available, but the motherboard simply ignored its 26.66x data rate ratio (which is actually a 10x memory multiplier on a 4/3 internal memory controller ratio using a 100MHz base clock and DDR). The default DDR4-2133 ratio was instead applied to a 125MHz BCLK to match the rated DDR4-2666.

I could have proceeded from here using a 32x CPU ratio to maintain my previous 4GHz CPU test frequency, but I decided to forgo the 1.25x ratio in light of its instability on several of our previously-tested boards. The DDR4-2666 ratio for a 100MHz BCLK is available on every enthusiast-class X99 motherboard we’ve tested.

Full details of my DDR4 test platform are available in my previous review.

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  • blackmagnum
    I have to ask: Do these aluminum clip-on heat spreaders help with lowering the temperature or they just like huge spoilers on Honda Civics (I look fast)?
  • COMONGUISE
    I have to ask - When will Tom's show a comparison with DDR3? I know its on a different chipset, but we would really like to know.
  • tom10167
    They won't do that because then nobody would buy any DDR4 ram
  • SuperVeloce
    @tom10167: Well yeah, 1600 ram is enough for 99% home usage scenarios, no matter how much faster a DDR4 can be. But now you can already get 2666 cl15 ram (latency something like ddr3 1600mhz cl7, cl8), and if that's at 1,2V, even better. First ddr3 ram sticks for first amd ddr3 chipsets and core2 intels were terrible and with high voltage for faster models (I even saw 1,7V+). So in a way this time around latency drops faster and it's not even available yet in mainstream platforms...
  • Crashman
    1893522 said:
    I have to ask - When will Tom's show a comparison with DDR3? I know its on a different chipset, but we would really like to know.
    Different processors make an inaccurate comparison, but you can compare two articles if you like. In fact we used the same benchmarks so that you could.

    On the other hand, comparing two articles to prove that DDR4 currently performs slightly worse than DDR3 is a futile task. Anyone who buys LGA 2011-v3 does so for its added PCIe lane OR added CPU cores. They have no choice other than DDR4.

    1631703 said:
    They won't do that because then nobody would buy any DDR4 ram
    Right, go ahead and pair DDR3 with your Core i7-5930k. Tell us how it goes. Thanks.
  • codo
    everything on my machine is blitzing as it should be but just cause I know this exists I want it.
  • CaedenV
    Quote:
    I have to ask: Do these aluminum clip-on heat spreaders help with lowering the temperature or they just like huge spoilers on Honda Civics (I look fast)?

    To say that it did not help at all would be a lie... but it is mostly for looks.

    Quote:
    I have to ask - When will Tom's show a comparison with DDR3? I know its on a different chipset, but we would really like to know.

    When Skylake comes out we should see the first chips that can support DDR3 and DDR4 so we can see some true head-to-head comparisons. I suspect that DDR4 is (at least at the moment) no better than DDR3 in performance and only has an advantage in a performance per watt perspective. But like Crashman said: The first DDR3 modules (and controllers) were horrible and no better than DDR2 at the time. At least DDR4 is improving faster, and dropping in price sooner, than DDR3 did.
  • kardinin
    @blackmagnum Love your comment. Spoilers on a front-wheel-drive car. Hurk hurk hurk.
  • DDR4 is a bad joke right now. Kits are expensive, slow and low capacity. Where are the 16GB sticks? Timings of 15-15-15-35-2T?
  • CaptainTom
    Damn these prices need to come down. I would maybe pay half the asking price.
  • Niva
    My phenom 2 with ddr2 is starting to look obsolete... nah, I can get another decade out of it!
  • cd000
    At what point does latency overrule frequency? I'm looking at my Corsair Vengence DDR3 1600 Cas 9 kit, and then looking at the CPUz screenshot showing CAS 15 @ 1066 (2133, yes?) and wonder if my kit might not be faster.

    Secondly, out of curiosity, would it be possible to adjust the timings down to typical Cas 9 settings, and see how fast you could get the DDR4 to go?
  • SinxarKnights
    At what point does overclocking lose any real value? I think this is a prime example of it. You are overclocking this stuff for a increase in microseconds (and nanoseconds... really?) in benchmarks. Who cares? Too much effort for no gain IMO.

    Unless it was the point of the article to demonstrate there is so little difference in DDR4 speed vs performance gain that you might as well go for the cheapest possible.
  • Drejeck
    Quote:
    I have to ask - When will Tom's show a comparison with DDR3? I know its on a different chipset, but we would really like to know.

    Just look at the bandwidth. It doesn't represent real world performance gain though. Ram performance always depend on the CPU controller.
  • Crashman
    1049604 said:
    At what point does latency overrule frequency? I'm looking at my Corsair Vengence DDR3 1600 Cas 9 kit, and then looking at the CPUz screenshot showing CAS 15 @ 1066 (2133, yes?) and wonder if my kit might not be faster. Secondly, out of curiosity, would it be possible to adjust the timings down to typical Cas 9 settings, and see how fast you could get the DDR4 to go?

    You know the math really isn't that hard. DDR3-1066 CAS 5 has the same latency TIME as DDR3-2133 CAS 10. Just divide and multiply...or remember that cycle time is the inverse of frequency (easier to divide and multiply) :)

    DDR3-1600 CAS 9 was our previous "standard". That would be the same latency as DDR3-2133 CAS 12. Not too tough right? That means we need JEDEC to move forward on a DDR4-2133 CAS 12 standard as well.

    But they probably won't. JEDEC approved DDR3-1600 CAS 9 a couple years after DDR3-1600 CAS 11. Immediately following that, a couple companies started making memory that defaulted to DDR3-1600 CAS 9. And then, those companies stopped using the newer standard a reverted to the old.

    Now we have DDR4-2133 CAS 15 and, having learned from the DDR3-1600 CAS 9 fiasco, they'll probably never update it to lower latency. Performance seekers will be stuck with XMP forever.
  • Sabishii Hito
    I'm not surprised the reviewer hasn't been able to find anything to outclass the G.Skill Ripjaws 3000C15 sticks, early batches of those could overclock like nobody's business. The newer batches, not so much.
  • Sabishii Hito
    I do find it odd that most of the recent reviews of this kit actually have been of older batches (2014 earlier than week 40 as evidenced by the first four digits of the serials) and are Ver5.29 (Hynix) while most of the stuff out in the wild now is 1440 or newer and Ver4.23 (Samsung) and is much weaker at running tight timings. Corsair may be cherry picking the kits it sends out for review.
  • Xythras
    I would like Tom to TAKE OFF those aluminum clip-on heat spreaders and see whether is Kingston or Samsung written underneath. My money is on Kingston.
  • Crashman
    1778591 said:
    I would like Tom to TAKE OFF those aluminum clip-on heat spreaders and see whether is Kingston or Samsung written underneath. My money is on Kingston.
    To be fair, I quit doing the easy ones after opening some of the harder ones caused chips to be ripped-off the PCB :)
  • Sabishii Hito
    Kingston doesn't manufacture memory ICs. DDR4 at this stage is going to be either Samsung, Hynix or Micron, no matter the brand.
  • Crashman
    1549910 said:
    Kingston doesn't manufacture memory ICs. DDR4 at this stage is going to be either Samsung, Hynix or Micron, no matter the brand.
    I think he meant Micron, but shhhh no angry people today OK?
  • Cespenar
    Niva,
    DDR3 1600 cas 9 and phenom 2 x4 is still a great way to go. Todays games seem to run okay. Why upgrade for small return?